Spring Sublimation of the Seasonal Condensates on Mars from Omega/Mars Express

• Main Authors: Schmitt, Bernard, Douté, Sylvain, Langevin, Y., Forget, F., Bibring, J.-P., Bellucci, G., Altieri, F., Poulet, F., Gondet, B.
• Other Authors: Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2005
• Subjects: [SDU]Sciences of the Universe [physics]; North Pole
• Online Access: https://insu.hal.science/insu-00356756

abstract P23C-02 INVITED International audience The formation and sublimation of the seasonal deposits on Mars surface are major elements controlling its atmospheric circulation and its climate. A complex competition occurs between sublimation of CO2 frost, inter-hemispheric transports and snow deposition/condensation in the opposite polar regions. Water is released by different sources (caps, condensates, soil) but their locations and contributions are not yet well known. Before the Mars Express mission the evolution of the seasonal condensations have been essentially monitored by following the albedo and temperature changes of the surface (TES, MOC/MGS). Since January 2004 the OMEGA imaging spectrometer allows us to directly monitor the abundance, physical state and distribution of the CO2, water and dust components of the martian frosts and ices through their visible and near-infrared spectral signatures. In particular, the monitoring of the evolution of the frost composing the seasonal caps provides strong constraints on the microphysics of the sublimation/condensation/deposition processes of volatiles as well as on their seasonal cycle. The abundance of the dust co-deposited with ices should also constrain the dust loading and transport processes. We present the latitudinal evolution of the composition and physical state of the ices composing the seasonal deposits from the north pole to the crocus line, as seen by OMEGA. Then we describe the temporal evolution of the spatial distribution of CO2 frost and H2O ice during spring sublimation of the northern seasonal condensates. In particular a wide annulus of a thin layer of dusty water ice forms at the fringe of the recessing CO2 seasonal cap and moves towards higher latitudes as sublimation progress. All this information allows us to draw a coupled microphysical and latitudinal evolution sketch of the seasonal frosts. Implications and constraints on Mars GCMs will be analyzed.